Air pump



F. JOHNSON.

' AIR PUMP.'

- APPLICATION FILED JAN. 1B. 1921. f 1,438,918. Patented Dec. 12, 1922.

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application media-army is, i921.

To all eli/fom 'it may Concern.'

Be it lrnown that l, FRANK doiiNsoN, a

citizen of the Unit-ed States, residing' Aurora, in the county of lianeand State of Illinois, have kinvented certain 'new and useful Improvements in Air which thefollowing is a specilication.

rlhis .invention relates to air pumps and has for its principal object to generally improve upon pumps` of thisnature by pron viding a4 device which will be of extremelyk simple, durable and inexpensivey construction, one whichi's etiicient and reliable in operation, and well adapted to the purpose for which it is designed. i

With the above and numerousother objects in view, this invention 'comprises certain novel features of construction 'and arrangement of parts as will be hereinafter more fully described.

In the drawing The ligure is a vertical and longitudinal section taken through the pump.

eferring tov the drawings by numerals it will be seen that l designates the base having any suitable means such as the bolt 2 for attaching` same to a support. The upstanding wall 3 projects at right angles to the base l from its longitudinal side edges and pivotally supports the pump itself. The pump itself consists of the"main cylinder e and the auxiliary cylinder y5 which has a diameter smaller than that of the main cyl` inder. These cylinders extend longitudinally of each other and are in communication with each other having the valve seat 6 situated therebetween. A piston 7 is movably mounted in the main cylinder 4l and is lixed in any suitable manner to the piston rod 8. The end of this piston rod S extends a distance into the auxiliary cylinder 5 and is threaded so as to be connected to the rod 9 which is integral or otherwise fixed to the auxiliary piston l0 which is movable in the auxiliary cylinder 5.

A valve 1l is slidably mounted on the rod 8 and a. suitable washer l2 is disposed between the valve ll and the valve seat` 6. This valve 11 is cup-shape so as to form thereon a stuffing box 13. Suitable packing 14 is situated therein and firmly held by the gland l5. An annular groove is provided in the stuffing box 13 in which lits the wire 16 by abutting the valve seat 6 thus limiting the movement of the valve 1l from this valve seat,

Pumps, of?

the construction and operation Serial No. ll.

y .Particular attention is called to the cousti'ucticn of the pistons 'l' and l0. rEhe active faces of these 'pistons are cut away so to form a dovetailed annular shoulder il? for receiving` the concave-convex leather washer i8. main pist-on main cylinder Llbetween as the piston i is asshown in the drawing.

Jfin operating .lever 19 is pivotally' mount ed fon the base l andis pivoted intermediate its ends to the rod 9. Upon operation of the lever 19 ity will be seen that when saine is pushed to the left the Arod 9 will also be pulled to the leftthus moving pistons l0 and?.` yUpon movement of the piston 7 to the-leftwthe air contained in the cylinder et will be compressed and will ll to an open position so that the air will till up the auxiliary cylinder 5 as the piston l() is being moved to the left. ISwing to the fact that the capacity of the auxiliary cylinder 5 is smaller than that of the main cylinder 4l it will be readily seen that some of the air will be forced through the outlet 2O which may be of any preferred construction. After the piston 7 has come into engagement with the valve seat 6 and this end of the cylinder t the lever 19 will then be pushed to the right. The air which has been forced into the auxiliary cylinderwill now be compressed by the pistons l() and will force the valve ll to close and force the air through the outlet 90. ln the mean time thel air will be replenished in the main cylinder 4 since it will be allowed to enter through the space between the piston 7 and the inner wall of the main cylinder fl. lt will be readily seen by an inspection of the drawing, however. that this air can only pass by the piston 7 when it is traveling to the right or upon its non-compression stroke. Attention* is also called to the cylindrical cavity 21 which is provided centrally in the piston 7 so as to accommodate the stuiiing box 13 and gland l5, when kthe piston 7 is moved cont pletely to the left..

From the foregoing description, taken in connection with the accompanying drawing, of the device will be readily understood without a more extended explanation. As numerous changes in form, proportion, and in the minor. details of construction may be resorted to without departing from the spirit of the inn 7 is sli'htlv saaced from the so that airmay pass therepushed tothe right ltwill also be noted that the` force the valve main cylinder, a cheek valve situated in the outlet a main piston movable in the main cylinder and slightly spaced from its inner wall, `means carried by the main piston for allowing air to pass between the piston y and the wall as the piston moves away from the auxiliary cylinder, an auxiliary piston movable in the auxiliary cylinder, a second check valve constructed so as to allow a fluid to pass from the mainr cylinder to the auxn iliary cylinder only, means for connecting the two pistons, and means for operating the pistons.

2. In combination, a main cylinder, an auxiliary cylinder of smaller diameter than themain cylinder and situated so as to exa main cylinder, an`

tend longitudinally therefrom and provided with an opening communicating therewith, an outlet cheek valve situated in the auxiliary cylinder adj aoent the main cylinder, a cheek valve slidabley in the opening between the main cylinder and the auxiliary cylinder, said latter valve being substantially cup shaped, having an opening in its bottom, a main piston movable in the main cylinder means carried by the main piston for allowing air to pass between the piston and the wall `as the piston moves in one direction only, namely away from the aux.- iliary cylinder, an auxiliary piston movable in the auxiliary cylinder, a rod oonneoting the two pistons and passing through the opening in the cup shaped cheek valve, stuliing material disposed within the cup shaped valve about the rod,fand means for holding the-'stuffing material in plaoe. 4

In testimony whereof I aix my signature y in presence of two witnesses. v

'FRANK 'Joinvson JnLIUs y OTTO WEIs.

Witnesses:

F. Mmmm, 

